Retort assembly



1957' c. c. LOOMIS ETAL RETORT ASSEMBLY Filed Oct. 7, 1954 INVENTORS; I CHAUNCEY C. LOOMIS WILLIAM J. ASH

United States Patent RETORT ASSEMBLY Chauncey C. Loomis, Stockbridge, Mass., and William J. Ash, Salisbury, C0nn., assignors, by mesne assignments, to the United States of America as represented by the United States Atomic Energy Commission Application October 7, 1954, Serial No. 461,048

3 Claims. (Cl. 266-15) This invention relates to a new and improved apparatus for recovering volatilizable metals, such as magnesium and calcium, in substantially pure form. In particular it relates to an improved retort assembly having an elongated retort cover.

In the production of volatiliza'ble metals by thermal treatment and sublimation a high vacuum is employed in the retort and at the same time the retort is cooled at its unloading end and heated to very high temperatures at its furnace end. As a consequence, it frequently is difficult to maintain the necessary high vacuum required for efficient operation since the sealing means employed upon the retort cover is subjected both to thermal and pressure stresses and during the extended period of an operating cycle, may develop leaks. Accordingly, it is an object of our invention to provide an improved retort assembly in which the critical sealing surfaces are substantially relieved of thermal stress.

A second object is to provide a retort cover wherein the sealing surfaces are located intermediate the ends of the retort condenser sleeve.

Another object is to provide a retort cover having its sealing surface located between the retort cooling jacket and a retort cover auxiliary cooling means.

Still another object is to provide a retort cover having its sealing surface removed from the region of sublimed hot metal.

Other objects and advantages of the invention will be noted when the following description is read in conjunction with the drawings in which Figure 1 is an elevation view showing the general arrangement of the retort assembly when employing the invention and indicating in dotted lines a representative deposit of the metal produced therein and Figure 2 is a view taken along line 2-2 of Figure 1, the deposited metal being omitted for purposes of clarity.

As shown, a typical assembly comprises a conventional retort mounted within the furnace wall 11 and closed at its inner end. Temperatures of the order of 215 0-2200" F. are attained by this retort surface and the retort preferably may consist of 28 Cr-l6 Ni steel closed with a cast stainless steel cap 12. A normal cycle for the production of a deposit of metal may approximate 6-24 hours. The material to be subjected to the volatilization treatment may be deposited in the hot end of the retort as indicated diagrammatically at 13.

At its outer end the retort is provided with a slightly enlarged section 14 which is joined to section 10 by means of an intermediate section 15. At the region where the retort assembly emerges from the refractory furnace wall 11, a stainless steel wrap 16 encases the section 15.

The outer enlarged section of the retort preferably has an abutment or flange 20 secured thereto and is provided with a cooling jacket 21 extending along a substantial portion of the length of retort section 14. Any suitable cooling medium such as water may be circulated through this jacket for the purpose of enhancing the temperature differential between the inner hot section 10 and the outer 2,814,477 Patented Nov. 26, 1957 ICC section 14 of the retort assembly and thus establishing a cooler zone for deposit of the sublimed metal.

A hollow condenser sleeve 25, which is substantially longer than conventional condenser sleeves used in this type of apparatus, is adapted to rest within the enlarged outer section 14 of the retort in the cooler zone and projects outwardly a substantial distance beyond the flange 20. This elongated sleeve has the advantage of providing a much larger surface upon which sublimed metal may deposit, a typical deposit of magnesium metal being shown by the dotted section in Figure 1.

At its outer end the sleeve is provided with a series of apertures 26, serving as a means for anchoring various handling tools used in mounting and dismounting the sleeve in the assembly.

For the purpose of applying a vacuum to the retont one or more conduits 30 are attached to retort section 14 adjacent flange 20. The vacuum conduit may extend through the jacket 21 if desired, although this is not essential.

As an important feature of our invention, a specially shaped deep-cupped retort cover 31 is mounted over a projecting end of the sleeve and terminates in a flange 32. This flange is provided with a suitable sealing means such as gasket 33 adapted to seat upon a collar 34 forming a part of flange 20.

Suitable brackets 35 attached to flange 32 provide a means for positioning and supporting the retort cover in place while handles 36 serve as a convenient means for mounting and dismounting the retort cover on the assembly.

Upon application of vacuum through conduit 30 the cover is tightly held in place and the sealing means 33 is compressed against collar 34. The vacuum may for example involve a first roughing vacuum of about 200 microns pressure followed by a fine vacuum of about 50-100 microns pressure.

As will thus be noted, the sealing means is located adjacent the region of the cooling jacket and is removed from the region where hot vaporized metal is being deposited. Accordingly, the possibility of deterioration of the sealing gasket due to excessive heating while it is holding the high vacuum, is thus minimized. Molecules of the vaporized metal derived from charge 13 in the hot end of the retort tend to deposit upon the cooler surface of sleeve 25, a small amount of such metal meanwhile depositing upon the exposed inner surface of the retort cover, as indicated diagrammatically at 40. ht has been found that supplementary cooling of the outer surface of retort cover 31 does not materially affect the manner in which the sublimed metal deposits within the retort assembly, and our invention therefore comprehends the use of such supplementary cooling when desired, for the purpose of further eliminating thermal stress upon the sealing means. It will be understood, however, that such supplementary cooling is not necessary in all cases and the invention is not to be considered as limited to such use. When such cooling is desired it may be accomplished by any suitable means such as use of a second cooling jacket, use of an open stream of water or other liquid cooling medium, or use of a stream of cooling gas. One simple means of providing this desired effect may comprise the use of a water trickling arrangement wherein such water falls upon a fabric covering 41 and by evaporation causes a lowering of the temperature of the retort cover adjacent the flange 32.

It will be apparent that various changes may be made in the apparatus embodying the present invention without departing from the spirit and scope of the invention as defined in the appended claims.

What we claim is:

1. Apparatus for the thermal production of volatilizable metals including a retort having a furnace section and an outer condenser section, a removable, elongated, open condenser sleeve in said condenser section, a substantial proportion of the length of said sleeve extending beyond the end of said condenser section, a cooling jacket about said condenser section terminating at said end, a sealing flange for said condenser section forming a wall of said jacket at said end and a cup-shaped cover for said condenser section, said cover at one end abutting and capping said extending portion of the condenser sleeve and at the other end having a sealing means cooperating with said flange whereby said sealing means is cooled by the fluid in said cooling jacket and said sealing means is spaced from the surfaces on which hot metal is deposited.

2. Apparatus for the thermal production of volatilizable metals including a retort having a furnace section and an outer condenser section, a removable, elongated, open condenser sleeve in said condenser section, a substantial proportion of the length of said sleeve extending beyond the end of said condenser section, a cooling jacket about said condenser section terminating at said end, a sealing flange for said condenser section forming a wall of said jacket at said end, a vacuum connection extending into said condenser section adjacent to said end whereby it is cooled by the fluid in said jacket and a cup-shaped cover for said condenser section, said cover at one end abutting and capping said extending portion of the condenser sleeve and at the other end having a sealing means cooperating with said flange whereby said sealing means is also cooled by the fluid in said cooling jacket and said sealing means is spaced from the surfaces on which hot metal is deposited.

The apparatus of claim 2 including means for cooling the exterior of said cover whereby said flange and sealing means are disposed between two relatively cool surfaces.

References Cited in the file of this patent UNITED STATES PATENTS 1,594,348 Bakken Aug. 3, 1926 1,862,560 Willcutt et al June 14, 1932 2,401,170 Lepka May 28, 1946 

1. APPARATUS FOR THE THERMAL PRODUCTION OF VOLATILIZABLE METALS INCLUDING A RETORT HAVING A FURNACE SECTION AND AN OUTER CONDENSER SECTION, A REMOVABLE, ELONGATED, OPEN CONDENSER SLEEVE IN SAID CONDENSER SECTION, A SUBSTANTIAL PROPORTION OF THE LENGTH OF SAID SLEEVE EXTENDING BEYOND THE END OF SAID CONDENSER SECTION, A COOLING JACKET ABOUT SAID CONDENSER SECTION TERMINATING AT SAID END, A SEALING FLANGE FOR SAID CONDENSER SECTION FORMING A WALL OF SAID JACKET AT SAID END AND A CUP-SHAPED COVER FOR SAID CONDENSER SECTION, SAID COVER AT ONE END ABUTTING AND CAPPING SAID EXTENDING PORTION OF THE CONDENSER SLEEVE AND AT THE OTHER END HAVING A SEALING MEANS COOPERATING WITH SAID FLANGE WHEREBY SAID SEALING MEANS IS COOLED BY THE FLUID IN SAID COOLING JACKET AND SAID SEALING MEANS IS SPACED FROM THE SURFACES ON WHICH HOT METAL IS DEPOSITED. 